Known in the art is a composite stretchable member which can stretch in a first direction (see PTL 1). This composite stretchable member is provided with a first nonwoven sheet and a second nonwoven sheet which are superposed on each other and a plurality of elastic members which are arranged between the first nonwoven sheet and the second nonwoven sheet. The first nonwoven sheet and the second nonwoven sheet are joined with each other at joined parts which are provided discontinuously in the first direction and a second direction which is perpendicular to the first direction. The elastic members extend in the first direction while separated from each other in the second direction without passing through the joined parts and are fastened to the first nonwoven sheet and the second nonwoven sheet at the two ends of the composite stretchable member in the first direction. As a result, in the contracted state, the first nonwoven sheet parts between two joined parts adjoining each other in the first direction deform in convex shapes outward in the thickness direction at one surface of the composite stretchable member, while the second nonwoven sheet parts between two joined parts adjoining each other in the first direction deform in convex shapes outward in the thickness direction at the other surface of the composite stretchable member. As a result, at one surface of the composite stretchable member, a large number of pleats are formed in the second direction by the first nonwoven sheet, while at the other surface of the composite stretchable member, a large number of pleats are formed in the second direction by the first nonwoven sheet.